The subject matter of the application relates to a monitoring system for a data processing unit for visual representation of internal sequences. The data processing unit has a sequence program. The sequence program enters into connection with peripheral equipment of the data processing unit via an operating system. The data processing unit is connected with an evaluation unit via an interface such that by the data processing unit, items with information relating to internal sequences of the sequence program are transmitted to the evaluation unit via the interface, are evaluated, and are represented on a display screen.
From GB 2253542 A, a monitoring system is known that comprises the features described above.
For data processing installations, for the analysis of the individual internal sequences in the execution of a sequence program there are listing units, also called tracers, by those skilled in the art. For switching computers there are special call followers, also called call tracers by those skilled in the art. The listing units list the data received during a test run at the side of the operating system opposite the sequence program of the data processing units. After the test run, the data are available for subsequent evaluation.
It can hereby occur that the actual internal sequences can no longer be reconstructed unambiguously, because they may have been obscured on their path via the operating. An apparent error of the sequence program may actually have been caused by an error of the operating system. A nearly simultaneous co-tracing capacity is not given.